Yarn Length from Weight Calculator
Divide the length on the yarn label by its weight, then multiply by the net weight of your leftover yarn. Use the same yarn label as the partial ball, and subtract any cardboard core first.
No account needed. Calculations stay in your browser.
Enter values from 0 to 1,000,000,000. Positive measurements must be at least 0.001; stitch counts and repeats must be whole numbers.
- Estimated yarn left
- 70 m
- Project with allowance
- 66 m
- Estimated spare
- 4 m
- Additional matching balls
- 0
How the calculation works
Metres per gram = label metres ÷ label grams. Multiply by the net yarn weight for the estimated remaining length. Project length with spare = project metres × (1 + allowance ÷ 100). Compare those two lengths. If short, divide the gap by label metres and round up for whole matching balls.
Worked example
A 200-metre, 100-gram ball has 2 metres per gram. A 35-gram leftover holds about 70 metres. A 60-metre project plus 10% spare needs 66 metres, leaving an estimated 4 metres.
Check before you start
This estimate assumes the remaining yarn has the same metres per gram as the label. Scale precision, moisture and label tolerances affect the result. It cannot identify an unknown yarn, predict gauge or make a different fibre equivalent. A project length is an input, not a promise that a garment will fit. Check the dye lot before you buy more.
These calculations use the dimensions you enter and the stated layout rules. They do not measure fabric shrinkage, yarn tension or your working pace.
Next steps
- What Size Crochet Hook for Worsted Yarn?
- How Many Granny Squares for a Blanket?
- Crochet Hook Sizes Chart: mm to US and UK
- Open the crochet pattern generator
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